Yes. You can always do a composite veneer over a tooth or multiple teeth. But that is not the end of the story. You should also look at the end result of such a procedure over the short, mid and long term.
1) Short term consideration
You have to find a VERY skilled cosmetic dentist to make a composite veneer look good with well adapted margins and adequately pleasant contour. For this to happen, these skilled dentists will charge you as much as the average dentist will charge you for a porcelain veneer.
2) Mid term consideration
The composite veneer, in spite of all polishing techniques the skilled dentist will use to finish the outer surface, it will start changing colors after a few years. this change may not be aceptable if it is in front of your mouth.
Also the composite veneers are also more succeptible to chipping and fractures than a well made and well adjusted porcelain veneer.
3) Long term consideration
Because of #2 above the composite veneers will probably need to be redone after a few number of years.